17 August 2011

The failure of quantum gravity

Have a look at the overview article arXiv:1108.3269 "An introduction to quantum gravity" by Giampiero Esposito.

It lists 16 approaches to quantum gravity that were followed in the last 80 years - string theory is one of them. Then it lists their achievements. All are theoretical! Not a single of the achievements is a testable prediction.

Yep, quantum gravity is a dead alley. We all can stop reading gr-qc.


  1. I stopped my interest in cosmology, due to, what I believed was a dead end. Namely gravity being geometric and trying to force a unified theory by the theory of "gravitons". I have not found any mainstream scientists speak with your clarity. That is why, I decided to let you know, I appreciated the insight, by posting a comment.

    I am not a scientist. I am more like a scientific fan. But fans know a stinky strategy when they see one.

    I have studied the approaches to quantum gravity. I feel for their authors. It must be professionally frustrating to have successfully explained three of the four forces by quantum theory.

    But from afar, I seen thirty years of string theory and M-Theory, lead to ruined scientific careers.

    Even a pedestrian observer of science, knows that i) blackboards w/o experiment is less than relevant, and ii) equations that take up many blackboards don't pass the "Occam's Razor" snicker test.

    The three forces of quantum mechanics have been proven by particle accelerators. The larger the land based accelerator; the better chance to find smaller particles.

    The fact that attempts at GUT, like string theory, to be proven, would require particle accelerators, light years in size; should be a sign to all young physicists that they are searching a holy grail.

    I love the Whitens, Steinhardts, and especially Turok. I appreciate their academic bravery, lack of egos and the ability to sound like regular people.

    But I can't help but feel sorry for them. I want to tell them they are like the main character in "Contact"; being told they are wasting their precious brains on something that can't be proven. And worse, what could they be using their special talents on to help other scientific pursuits?

    Which begs the question, from a fan: are today's theoretical physicists this myopic or do they already know how the game ends and are "playing it out"?

    I would love to get your perspective.

  2. John,

    supersymmetry, string theory and M-theory are dead. In cosmology, Turok and Steinhardt, like many others, write nonsense.

    Why don't these smart people do better? Because they are forced to do nonsense to get a career. A bad situation.